1991 MAP Failure???????????
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Intermediate
Joined: Mar 2009
Posts: 29
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1991 MAP Failure???????????
I've have a 1991 corvette that I inherited from my father. It sat for the last 5 or 6 years prior to my father passing away. The reasent problem that I have started to have is a loss of power. Two months ago I had the ACI valve replaced from the recommendation I got from this forum. The car was running like new. Then a month ago I drove it to work and on my return trip home it just started loosing power. When you pressed down on the gas pedal it would act like you were bogging the engine down. I pulled over and found a plug wire on the exhaust manifold. Got it off and it started right up. Replaced all plug wires. This weekend, drove it 300 miles ran like a champ. On my return home on Sunday 60 miles from the house it started doing it again. Got it home on the roll back and was going to start it up to limp it into the garage and it fired right and ran like a champ. There has been no service engine light either before or after when the problem happened. You guys came through on my last problem. Something that the " trianed " GM mechanics could figure out. So I back to the experts for help!!
Melting Slicks
Joined: Mar 2002
Posts: 3,252
Likes: 6
From: The Colony Tx
I am having the same problem with an 88 (MAF). It only does it when it has been running for a while. It finally decided to give me a code 33 so I know it is MAF related. Once the temps start going down I will try to find the problem.
Oh, I have found that if I pull over and turn the car off and then restart it will run just fine for a while. First time was on a trip from Dallas to Waco, about 110 miles. I pulled off the highway and checked under the hood and checked the tranny fluid. Everything looked OK so I got back on the road and it ran fine. On the way back it did the same thing. So if you have a problem while driving try the off/on and see if you can continue to drive the car.
Oh, I have found that if I pull over and turn the car off and then restart it will run just fine for a while. First time was on a trip from Dallas to Waco, about 110 miles. I pulled off the highway and checked under the hood and checked the tranny fluid. Everything looked OK so I got back on the road and it ran fine. On the way back it did the same thing. So if you have a problem while driving try the off/on and see if you can continue to drive the car.
Pro
Joined: May 2006
Posts: 637
Likes: 0
I've have a 1991 corvette that I inherited from my father. It sat for the last 5 or 6 years prior to my father passing away. The reasent problem that I have started to have is a loss of power. Two months ago I had the ACI valve replaced from the recommendation I got from this forum. The car was running like new. Then a month ago I drove it to work and on my return trip home it just started loosing power. When you pressed down on the gas pedal it would act like you were bogging the engine down. I pulled over and found a plug wire on the exhaust manifold. Got it off and it started right up. Replaced all plug wires. This weekend, drove it 300 miles ran like a champ. On my return home on Sunday 60 miles from the house it started doing it again. Got it home on the roll back and was going to start it up to limp it into the garage and it fired right and ran like a champ. There has been no service engine light either before or after when the problem happened. You guys came through on my last problem. Something that the " trianed " GM mechanics could figure out. So I back to the experts for help!!
I would start to see if there are fault codes stored (even without the ses light on).
And since it is a 91, test the injectirs also with a voltmeter set to measure ohm.
A description is shown in one of the videos in the sticky´s up the page, look for FIC injectors.
Take a look under the hood to see what color the injectors are, are they grey/metal, then they are most likely the original ones wich are not the best ones.
They were used on the 89-90-91 Corvettes.
Just a few free things to check.
Burning Brakes
Joined: May 2007
Posts: 965
Likes: 13
From: turn 12 at Road America or TX
Do you see the check engine light when you turn the ignition on? the indicator bulb might be removed or burned out. As mentioned earlier, check for codes anyhow.
Check fuel pressure - connect a gauge and take a drive. Other possibles are a flakey ECM or a clogged catalytic convertor. My 91 had an ECM crap out, but it would set several random codes and it acted similar to yours.
Check fuel pressure - connect a gauge and take a drive. Other possibles are a flakey ECM or a clogged catalytic convertor. My 91 had an ECM crap out, but it would set several random codes and it acted similar to yours.
